The U.S. Environmental Protection Agency is preparing to ban the sale of certain rodenticides to the general public, a move which could help prevent one of the most frequent causes of pet poisoning.

In addition to banning the most toxic anticoagulant rodenticides (brodifacoum, bromadiolone, difethialone and difenacoum), the agency also plans to stop the sale of most loose bait and pellet-form rodenticides to cut down on accidental poisonings of children and pets.

The EPA set a June 4 deadline for rat and mouse poison manufacturers to come up with products that would be safer for children, pets and wildlife. According to the agency, many producers abided by the EPAs guidelines and developed safer bait delivery systems with less toxic bait. Several companies refused to change their products and the EPA is now taking steps to ban those companies from selling their products. The companies that EPA is targeting are:

According to the Merck Veterinary Manual, anticoagulant rodenticide poisoning is the most frequent cause of poisoning in pets. While older versions of anticoagulant rodenticides such as warfarin required multiple ingestions to result in toxicity, the latest products require only one feeding to be highly toxic.

"New products have a longer biologic half-life and therefore prolonged effects (which require prolonged treatment)," according to Merck. "For example, the half-life in canine plasma of warfarin is 15 hr, diphacinone is 5 days, and bromadiolone is 6 days, with maximum effects estimated at 12-15 days. Brodifacoum may continue to be detectable in serum for up to 24 days."